I'm not a natural guitar player so I can't do it by ear. I like the guitar loops, and how they fit with my songs, but now I want to record them myself. This is the most frustrating thing.
MacBook Pro with Retina display, iOS 10.2.1
You can only see this in GarageBand for the virtual instrument loops. There you can see the notes in the Track Editor in the score view. For the real instrument loops you would have to open the loops in a program that will analyze the chords - for example Logic or Melodyne. The free Audacity can help you to extract the chords by showing the frequency spectrum.
Is there a way to figure out the chords that Garageband guitar loops are strumming?
